When a middle child - typically of a family of three kids who are close in age - feels left out or neglected.

Because the bigger sibling is the first born and typically an over-achiever, they are the most important and get the most privileges. A younger sibling is the 'baby' of a family and gets away with more as well as being the most looked-after. Middle-child syndrome starts when the middle child is squeezed between these two and have trouble finding their 'niche' in the family.

Middle children will sometimes...
-misbehave to get attention
-go with the flow
-work as little as possible
-be less parent-dependent then their siblings
-become the 'loner' of the family, not participate in family events unless told to.
-play the peacemaker
-be more likely to go to a friend for advice than a parent
-be very creative

In short its where the older child gets all the awards, the younger gets all the love, and the middle gets nothing.

(A real-life example of what happened to my younger sis, who suffers from middle child syndrome)

Oldest: Hey I just turned 16!
Mom: Lets go pick you out a car!
Oldest: Yay!

-1 1/2 yrs later-

Middle: Hey I just turned 16!
Mom: Oh.. er.. well we're still paying for your sib's car, so you'll have to just borrow from her when you can..
Middle: >.>

-2 yrs later-

Youngest: Hey! I just turned 16!
Mom: Yay! And I just finished paying for the other car! Lets go get you a car!
Middle: Hey! I should be the next one to get a new car!
Youngest: but its MY birthday
middle: Thats stupid
youngest: MOMMY SHE JUST CALLED ME STUPID!!
mom: Be nice to your little sister on her birthday!! Come on, birthday-girl! Lets go get that car!
Youngest: WOO!

The Urban Dictionary Mug

an emotional scarring condition.
Middle children are known for ending up with the things that are too big for the baby in the family and too small for the oldest.
it is a known fact the youngest and oldest are treated differently than the middle child for the oldest is the first child aka favorite
and the smallest is the baby aka the last child known for getting whatever they desire because they are the "baby"

Middle Children sydrome includes
neglect, forgotten dates, and sometimes in bad cases forgetting they even exist.

i lived through this condition,
it is not fatal
just difficult.

a first born: OH i just got this GREAT new car!
a middle child: oh...i have to wait until my sister wrecks hers...then i can have that and they will get her a new one
a first born: oh Middle Child Syndrome, i see.

The Urban Dictionary Mug

A disposition that generally arises with the middle child of three children in a household. Middle children often lack the attention that the oldest (the most important child) and the youngest (the parent's favorite child) receive.

The Urban Dictionary Mug

Middle Child Syndrome is when a child is born in between other child and feels negleted. The middle child is faced threw challenges such as feeling like nothing, not worth, no one caring, ect. An Older child gets lots of attention, and gets everything first. They are the "most dependable" ones through the eyes of family members/parents. The younger child also known as "the baby" of the family gets most attention. This child gets the most attention and can get away with anything. They usually have less discipline. The middle child is usually left without anything. People tend to not notice they're there.the end up feeling left out and forgotten.parents don't usually focus on there needs only their dire emergencies. Middle children seek love and happiness through friends and become social butterflies. But through Neglection by parents the child drifts away and becomes a loner with family.

Mom: sorry honey but I just paid school fees can't really afford any birthday presents right now, if it helps I didn't get your (older) sister anything.
Middle: it's fine (mind: it's fine if you can't afford anything, but seriously a card is like a dollar, just a dollar. Glad I'm not worth a dollar)
(When middle child confronts people about how they feels other are like sure that HAPPEND... Middle child syndrome

The Urban Dictionary Mug

A child in a family is neither first or last is called the middle child. In a 3 child family, it is the 2nd child, etc.

This child usually gets the least amount of attention, because he/she is not the parent's first, and not deemed as 'special' enough, and is not the parent's last, and so is not treated like the baby.

This creates social tension between the family. The middle child would be the outcast while the rest of the family can have a laugh with each other.

However, in a family where there are seperate parents, creating half-siblings, where the child is in the middle of one side of the family, and is the first or only child in the other side, the middle child may become brattish, and demand everything he/she wants because he/she can get away with it with the other parent.

In the case of bratty middle children, the oldest usually looses out and then becomes the outcast, being independant and deals with how they recieve less attention than the middle child.